This invention relates to pet access doors and more particularly to a modular version of pet access doors and frames.
Pet access doors allow the passage of small pets through holes in doors or walls. Originally they consisted principally of a frame mounted on the surface of the door or wall at the edges of a hole that had been cut, and a door hinged on the frame to keep the elements out but to allow passage of a small animal through the hole by its pushing against the hinged door. For security purposes a frame was often mounted on the inside surface of the door or wall, with some arrangement for a sturdy security panel to be affixed to this inside frame so that it was not removable from the outside. Examples of such frames can be found in the present inventor's earlier U.S. Pat. Nos. 4,408,416 and 4,651,793.
When the frames are mounted on the exterior surfaces of the inside and outside of the door or wall in which a hole is cut, however, the interior portion of the door or wall that is exposed by the cut may not be sufficiently covered by the inside and outside frames. This is unattractive; it may be dangerous to the pet using the door; and it may allow access to the inside security panel fasteners. Attempts to alleviate this problem include putting horizontally extending walls on the inside and outside surface mounted frames to cover the interior of the hole. Since doors and walls are of different thicknesses, however, having a fixed depth of horizontal wall on the frame is problematical.
One solution to this problem is to have a horizontal wall member with break-away elements so that unneeded portions of the horizontal walls could be broken off. To make the break away portions convenient to break away, however, is also to make them relatively vulnerable to tampering. Also, if somebody assembling such a unit makes a mistake and breaks away too much of the wall portion, there is no opportunity to rectify the mistake.
The goals of any good pet access door unit are security of the building in which the door is used, functionality (that is, that it be convenient to use and provide protection from the elements for the building in which it is used), appearance, and strength. It is an object of this invention to provide a modular construction of a pet access door unit that meets these goals. Other objects are to allow use of two flaps in a constructed unit, to provide a security cover that may be applied in a horizontal motion, to allow attachment or removal of a flap to or from the frame while the frame is in place, and to provide for an automatically adjustable magnetic sill.